The current invention relates generally to a modified pulse width modulator (MPWM) in a power supply system that allows an operator to modify the output of the power supply without the need to physically access the power supply system itself. More particularly, the present invention relates to an innovative modified pulse width modulator (MPWM) connected to a power supply system utilizing a central processing unit (CPU) to control the inputs to get the desired output out of a power supply system.
Traditional power supply units are of analog in nature, utilizing an analog pulse width modulator (APWM) to control the frequency and duty cycle for an output voltage. A traditional analog power supply is shown in FIG. 1, depicting the components and operations of an analog power supply.
FIG. 1 shows the various components of a traditional analog power supply system 100 containing a power input 101, an electromagnetic interference (EMI) filter 102, and a transistor 108, all located on the primary side 104 of the traditional analog power supply system 100. On the secondary side 106 of the traditional analog power generator system 100, various components such as a rectifier 110, an error sensor 112, and a power supply output 122 are shown in FIG. 1. A power supply for CPU 120 within the traditional analog power supply system 100 is comprised of a transformer dividing the power from the primary side 104 from the secondary side 106 to eventually deliver power to the CPU 118. Finally, traditional analog power supply system 100 also contains a feedback loop 111 that reports the error at the power supply output 122 using an error sensor 112 and relays the error to an analog pulse width modulator (APWM) 116 on the primary side 104 through an isolation component 114.
It is worth noting that traditional analog power supply systems 100 are continuous, linear, and non-intelligent systems, and the analog pulse width modulator (APWM) 116 is used to control the pulse width and maintain the output voltage at power supply output 122. The analog pulse width modulator (APWM) 116 adjusts the pulse width based on the error detected by the error sensor 112 coming back from the feedback loop 111 when the output deviates from the desired output.
Traditional analog power supply system 100 does not adapt well to situations where the power supply output 122 needs to be changed. In order to change the power supply output 122, the entire analog power supply system 100 needs to be disconnected and various new parts needs to be installed before the traditional analog power supply system 100 can produce a different power supply output 122.
Turning now to FIG. 2, which shows a digital power supply system 200 that address the deficiencies of an analog power supply system 100 as identified above in FIG. 1. A digital power supply system 200 utilizes a microprocessor 216 instead of an analog pulse width modulator (APWM) 116 (see FIG. 1) to provide a discontinuous and intelligent control that is capable of making adjustments to the power supply output 222 without changing physical components. However, in order to make adjustments to the microcontroller's 216 behavior, an operator still needs to physically access the microcontroller 216 in order to reprogram it.
FIG. 2 shows the digital power supply system 200 containing a primary side 204 and a secondary side 206. The primary side 204 contains a power input 201, an electromagnetic interference (EMI) filter 202, a transistor 208, and the microcontroller 216 mentioned above. The microprocessor 216 in this prior art embodiment is used to control the pulse width associated with error adjustment instead of using the analog pulse width modulator (APWM) 116 (see FIG. 1) as seen in analog power supply system 100 (See FIG. 1). The digital power supply system 200 also contains a secondary side 206 with a rectifier 210, an error sensor 212, a feedback loop 211, a central processing unit (CPU) system 218, and a power supply output 222. Finally, digital power supply system 200 also contains a feedback loop 211 that reports the error at the power supply output 222 using an error sensor 212 to the microcontroller 216 on the primary side 204 through an isolation component 214.
The microcontroller 216 in the digital power supply system 200 is capable of functioning like an analog pulse width modulator (APWM) in creating a pulse width to compensate for the error detected by error sensor 212. It is advantageous to use a microcontroller 216 instead of an analog pulse width modulator (APWM) 116 because a microcontroller 216 provides an intelligent, dynamic control over the output of the power supply 200. Moreover, a digital power supply 200 reduces the total part count and allows the power supply output 222 to be operated in the discontinuous mode.
However, although microcontroller 216 contains memory and a processor, the microcontroller 216 is independent apparatus deriving its power directly from the power input 201. Because of this, the microcontroller 216 needs to be reprogrammed for a new power supply output to be implemented; this requires a physical interaction with the microcontroller 216.
Hence, it can be seen that there is a need for an innovative modified pulse width modulator (MPWM) that can address the drawbacks of both the analog pulse width modulators (APWM) and the microprocessors in their inability to adjust the output needs remotely without having to physically replace components or reprogram the microcontroller 216.